Double-end threaded body and internally-threaded body

Abstract

An object of the present invention is to provide a duplex threaded body having a right-handed thread and a left-handed thread on the circumferential surface of a single solid member. In addition, an object of the present invention is to provide a single-nut or double-nut type internally-threaded body that demonstrates a locking effect even at an intermediate position without substantially loosening by using a combination of a duplex externally-threaded body and one or more internally-threaded bodies. Moreover, an object of the present invention is to provide a screw structure in which a pair of internally-threaded bodies can only be removed by destruction once they are mutually coupled when screwed onto a duplex externally-threaded body, thereby making it possible to impart tamper-proof characteristics in addition to a locking effect. The duplex externally-threaded body of the present invention has, on the outer circumferential surface of a rod-like member, an overlapping region in which a clockwise spiral right-handed thread and a counter-clockwise spiral left-handed thread are provided in at least an overlapping manner. Moreover, the present invention makes it possible to use, alone or in combination, a right-handed internally-threaded body in which a right-handed thread is formed, and a left-handed internally-threaded body in which a left-handed thread is formed, that are screwed onto a duplex externally-threaded body.

Description

TECHNICAL FIELD[0001]The present invention relates to a threaded body having spiral threads formed in the outer circumferential surface or inner circumferential surface of a fixing member, and more particularly, to a duplex threaded body having a right-handed thread and a left-handed thread in which the spiral threads are composed of a clockwise spiral thread and a counter-clockwise spiral thread.BACKGROUND ART[0002]So-called screws, which are comprised by forming a thread along spiral path, namely a helix, depicted on the outer circumferential surface of rod by moving the center of a circular path along the central axis of the rod, have proliferated extensively as fundamental components used in industry. When broadly categorized according to the direction in which their threads are wound, screws are classified into right-handed screws, in which the thread extends clockwise in the positive axial direction, and left-handed screws, in which the thread extends counter-clockwise in the ...

AI Technical Summary

Benefits of technology

[0016]In addition, an object of the present invention is to provide a single-nut type internally-threaded body that does not loosen substantially even as a single nut and demonstrates locking effects even at an arbitrary intermediate position by combining the use of a duplex threaded body having a right-handed thread and a left-handed thread on the outer circumferential surface of a rod-like member, namely a bolt, and one or more internally-threaded bodies, namely nuts, or a double-nut type internally-threaded body that does not loosen substantially and demonstrates locking effects even at an arbitrary intermediate position by combining the use of two or more nuts.

[0058]In addition, by employing a suitable structure for the coupling structure of the two internally-threaded bodies, when the pair of internally-threaded bodies are screwed onto the duplex threaded body, once the internally-threaded bodies are mutually coupled, they can only be uncoupled by destruction, thereby making it possible to impart so-called evidence of tampering or evidence of non-tampering as a result of demonstrating tamper-proofing effects in addition to locking effects.

Problems solved by technology

Right-handed screws have been nearly exclusively used in conventional screw applications including bolts and nuts used for fastening, while left-handed screws have been limited to special applications such as turnbuckles in which internal threads are formed rotating in different directions along the same axis on both ends thereof.

This type of fastener is composed so that it is difficult for a nut screwed onto a bolt to become loose by making suitable design contrivances to the nut.

In addition, in the case of conventional single-nut type anti-loosening nuts, although a certain degree of locking effects can be obtained with a single nut, since urging force is simply generated with a washer-like plate piece to tighten meshing of the bolt and nut in a single spiral groove on the outer circumferential surface of the bolt, loosening of the nut is not substantially prevented, while in the case of a double-nut type, which is ultimately similar to the case of a single-nut type, since a reduced-diameter end of a first nut is reduced in diameter by a second nut, and the inner circumferential surface provided with irregularities on the reduced-diameter end is simply pressed to tighten meshing between the nut and bolt in a single spiral groove of the outer circumferential surface of the bolt causing loosening to be inhibited by frictional force between the outer circumferential surface of the bolt and the inner circumferential surface of the nut, both of these cases had the problem of the nut ending up loosening gradually due to vibrations and the like.

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